Another great example of a question that does not deserve an answer is “how many webpages are there on the Internet?” Any answer would be misleading because you have to first define what a webpage is, and then consider that thousands of sites contain thousands of pages that are dynamically user-generated, so if they’re different every time you visit – how do you count those? If a webpage pulls in data from a database and recombines them into something new for every session, does that count as a unique page?
So the question presupposes that webpages are discrete things that can be counted, and they’re not. Websites, on the other hand, are a little easier to count. Top-level domains like www.amazon.com are quantifiable. Even that, though, brings up the question of subdomains. Does ec2.images-amazon.com count as a website? It could stand on its own if Amazon wanted it to. So, there’s still some room for error.